JP2569590B2 - Optical disk device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A Industrial application B Outline of the invention C Conventional technology (Fig. 4) D Problems to be solved by the invention (Figs. 4 to 6) E Means for solving problems (Fig. 1) F Effect (FIG. 1) G Embodiment (FIGS. 1 to 3) H Effects of the Invention A Industrial Field of the Invention The present invention relates to an optical disc device, and for example, to an optical information processing device such as a magneto-optical disc device. It is suitable for application.

B SUMMARY OF THE INVENTION The present invention relates to an optical disk device, which seeks to a target track in a much shorter time than before by correcting a drive signal for driving an optical head using reproduction track data obtained during a seek. The operation can be completed.

C Prior Art Conventionally, in this type of magneto-optical disk apparatus, an optical head mounted with an optical head is driven and controlled by a predetermined amount to seek the optical head to a predetermined recording track.

That is, as shown in FIG. 4, in the magneto-optical disc device 1, a reproduction signal _SRF is obtained from a predetermined recording track of the magneto-optical disc 3 attached to the spindle motor 2 and rotating via the optical head 4. , To the address decoder circuit 5.

The address decoder circuit 5 to obtain reproduction data by demodulating the reproduced signal S _RF, now CRC (cyclic redeundancy ch
After obtaining accurate reproduction data without a read error by the eck method, a recording track (that is, a recording track of a magneto-optical disk being reproduced by the optical head 4 is referred to as address data of the reproduction data, hereinafter referred to as a reproduction track). the reproduction tiger poke data D _TRF representing the number) to the seek amount setting circuit 6 separates.

The seek amount setting circuit 6 converts the target track data D _TJ indicating the number of the target recording track (hereinafter referred to as the target track) for seeking the optical head 4 to the reproduction track data D _TRF.
By subtracting the reproduction track data D _TRF from the target track data D _TJ , the seek amount from the reproduction track to the target track and the seek direction (that is, whether it is on the inner side or the outer side of the magneto-optical disc 3). Represents)
And the detection data D _TD is _supplied to the target signal generation circuit 7.
Output to

On the other hand, as shown in FIG.
In the method, a pre-groove 10 is formed in advance so that a recording track 9 in which a pit 8 continues according to recording data is interposed, and reflected light obtained from the pre-groove 10 is detected to detect a tracking error signal. And the tracking control of the optical head 4 is performed based on the tracking error signal.

Thus, in the seek, when the light head 4 is connexion move transected recording tracks 9, the traverse signal S _T which changes optical head 4 is the signal level at the timing across the pregroove 10 in place of the tracking error signal Obtained
It is possible to detect the actual movement amount of the optical head 4 based on the traverse signal S _T.

Target signal generating circuit 7 on the basis of such principle, receives a traverse signal S _T through the traverse detection circuit 11, an amount corresponding to the detection data D _TD output from the seek amount setting circuit 6, for moving the optical head forming a target signal S _1.

That target signal generating circuit 7 is composed of a traverse count circuit and analog-to-digital converter (not shown), after excisional the seek amount detection data D _TD to traverse count circuit, the signal level change of the traverse signal S _T Each time the count value is counted down.
Furthermore, by outputting the count value via the analog-to-digital converter circuit, immediately after the start of the seek, after the signal level by the count content was rising or falling month according to the seek direction, the seek amount of detected data D _TD When the optical head 4 moves by only this amount, the target value signal S ₁ whose signal level falls to 0 level is output to the seek control circuit 13.

Seek control circuit 13, a speed detection signal S _V representing a speed of movement of the optical head received via the seek speed detecting circuit 14 during the seek, the difference signal S _REF and the speed detection signal S _V and the target value signals S ₁ Is output to the actuator drive circuit 15.

Actuator driving circuit 15, the difference signal S _REF and drives the actuator 16 provided with the light head and outputs a drive signal S _D based on, thus the target value signals S ₁ of the signal level and the speed detection signal S _V signal level The drive of the actuator 16 is controlled so that the optical heads 4 coincide with each other, so that the optical head 4 can be moved to the target track input to the seek amount setting circuit 6.

D Problems to be Solved by the Invention However, in this type of magneto-optical disc device,
In some cases, the actual movement amount of the optical head 4 cannot be accurately detected.

That is, from the light head 4 the signal level of the traverse signal S _T at the timing across one of the recording track is changed, the seek speed of the optical head 4 is increased, the higher the frequency of the partial traverse signal S _T.

In such a case, the noise components mixed into the traverse signal S _T, in practice the traverse signal consists S _T is difficult to reliably remove the noise components, counting traverse counting circuit of the target signal generating circuit 7 is erroneously It is difficult to detect an accurate movement amount.

Similarly, for example, when dust adheres to the recording surface on the magneto-optical disc 3 or when there is a defect such as a scratch,
When the optical head 4 moves thereon, the traverse signal S _T
And it is difficult to correctly detect the amount of movement.

Also, when the optical head 4 moves on the pit 8 as well as the pre-groove 10, a change occurs in the amount of the reflected light. Therefore, even though the optical head 4 does not cross the pre-groove 10, , the signal level of the traverse signal S _T is to vary, resulting the same problem as the above case.

In addition to this, as shown in FIG.
A magneto-optical disc 1 of a composite continious format (composite continious format) in which a portion 10 is cut out to form a mirror area ARM therebetween.
In 9, when light head 4 crosses the mirror area ARM does not change the signal level of the traverse signal S _T, thickness is difficult problem to accurately detect the moving amount of the optical head in this case Was.

In the target value signals S ₁ outputted Thus from the target signal generating circuit 7, in a position the light head 4 which has passed a position or target track in front of the target track, such a signal level is 0 level connexion, optical head There was a problem that the seek operation of No. 4 was completed there.

Therefore conventionally, based on the reproduction signal S _RF movement of the optical head 4 is completed to obtain a reproduction tiger poke data D _TRF, the movement of the newly optical head in the case of this compared with the target tiger poke data D _TJ do not match It was to be repeated.

Therefore, there is a problem that the time required for the entire seek to the target track becomes longer.

The present invention has been made in view of the above points, and it is an object of the present invention to propose a magneto-optical disk device capable of shortening the time required for the entire seek to a target track as compared with the related art.

In the present invention for solving means above problems to solve E problems, when the optical head 4 is moved in a seek operation, the recording track number to the target track, counting on the basis of the traverse signal S _T A traverse count circuit 25; and optical head drive means 13 and 1 for moving the optical head 4 in a direction crossing the recording track based on the count value of the traverse count circuit 25.
And 4,15,16,26,27,28, based on the reproduction signal S _RF which light head 4 is obtained when the connexion move transected recording tracks, reproducing a recording track of the optical head 4 crosses tiger poke data D _TRF , D _TRF1 and D _TRF2, and a seek amount correction circuit 30 and (31) for correcting the count value of the traverse count circuit 25 based on the reproduced track data D _TRF , D _TRF1 and D _TRF2. Be prepared to have.

F action At the time of seek, the reproduction track data D _TRF , D _TRF1 , and D _TRF2 are obtained, and the count value of the traverse count circuit 25 is corrected based on the data to thereby obtain the traverse count circuit 25.
By correcting the erroneous count, the optical head 4 can be moved to a position closer to the target track as compared with the related art.

Thus, the time required for the entire seek to reach the target track can be reduced accordingly.

G Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

In FIG. 1 in which parts corresponding to those in FIG. 4 are denoted by the same reference numerals, reference numeral 20 denotes a magneto-optical disc device as a whole, and a seek start setting signal S _ST , The target track data D _TJ and the reproduction track data D _TRF are given.

The seek amount setting circuit 22 subtracts the target track data D _TJ from the reproduction track data D _TRF based on the seek start signal S _ST when the magneto-optical disk device 20 enters the seek mode, and calculates the seek amount based on the result of the subtraction. and outputs the seek amount data D _D1 and seek direction data D _D2 representing the seek direction representing the target signal generating circuit 23.

Traverse counting circuit 25, after excisional that value by receiving the seek amount data D _D1 through the input circuit 24, the signal level of the traverse signal S _T is changed, this counts down the count value in response Output. Remaining tiger poke data D _N obtained representing the track number to the target track when the light head 4 is moved on the basis of the traverse signal S _T through the Supporting connexion traverse count circuit 25, digital-to-analog is the remainder tiger poke data D _N The data is output via the conversion circuit 26.

Selection circuit 27 on the other hand, switches the contacts based on the seek direction data D _D2, digital-to-analog converter
The output signal of 26 is received directly at one contact and is received at the other contact via an inverting amplifier circuit 28.

Gradually by the results shown in Figure 2, after the signal level according to the seek direction via the selection circuit 27 were rising or falling month, the traverse count circuit 25 counts down based on the traverse signal S _T the signal level can be obtained target value signal S ₂ which changes to 0 V, by outputting the target value signal S ₂ to the seek control circuit 13, following the change of the target value signal S ₂ Thus, the drive of the actuator 16 equipped with the optical head 4 can be controlled.

Thus, the seek control circuit 13, the seek speed detection circuit 14,
The actuator driving circuit 15, the digital-to-analog conversion circuit 26, the selection circuit 27, and the inverting amplification circuit 28 together with the actuator 16 constitute optical head driving means for driving the optical head 4.

Further, the magneto-optical disk device 20 has two seek amount correction circuits 30 and 31, and can correct the drive signal _SD by correcting the count value of the traverse count circuit at the time of seeking.

That is, in the seek amount correction circuit 30, the reproduction track data D _TRF obtained from the address decoder circuit 5 at the time of seeking is provided to the subtraction circuit 32 together with the target track data D _TJ , and the resulting difference data D _REF1 is _supplied to the comparison circuit 33 and It is given to the count value correction control circuit 34.

In practice, as shown in FIG. 3, at the time of seeking, the optical head 4 moves across the recording track of the rotating magneto-optical disk 3, so during the period T1 during which the optical head 4 moves at high speed, the reproduction is performed. It becomes difficult to obtain the track data D _TRF .

On the other hand, even during seek, when the optical head 4 moves at a low speed (that is, when the optical head 4 is decelerated before the optical head 4 is not sufficiently accelerated due to a small seek amount, or immediately after the start of seek and at the end of seek). Immediately before period), the magneto-optical disc connexion speed of movement of the optical head is relatively small with respect to the rotational speed of, Yotsute the recording tracks may be able to obtain a reproduction tiger poke data D _TRF.

Accordingly, in such a case, the reproduction track data D _TRF is obtained intermittently, and the number of tracks to the target track when the optical head 4 moves via the subtraction circuit 32 is determined based on the reproduction track data D _TRF. Can be detected.

Comparator circuit 33 receives the remaining tiger poke data D _N output from the difference data D _REF1 and traverse count circuit 25 consisting in the detection result, detects an error between the two data D _REF1 and D _N.

In practice, in the reproduced track data D _TRF obtained at the time of seeking, an error may occur in the value even though the error is detected by the CRC method.

However, since the error detection of the CRC method is performed, when an error occurs in reproducing tiger poke data D _TRF outputted, the values of the reproduction tiger poke data D _TRF is extremely in comparison with the value of the actual recording track It turned out that the values are very different.

A slave connexion reproduction tiger poke data D _TRF difference data D _REF1 obtained based on, by detecting the error between the remaining tiger poke data D _N obtained on the basis of the traverse signal S _T,
In smaller value range of the error, KaiTsuta that there is no error in reproduction tiger poke data D _TRF.

Therefore, when the error between the two data is equal to or smaller than a predetermined value, the comparison circuit 33 outputs the control signal _SC1 to the count value correction control circuit 34 to latch the difference data D _REF1 , and the difference data D _REF1
Is output to the input circuit 24 to correct the count value of the traverse count circuit 25 to the value of the difference data D _REF1 .

As a result, in the traverse counting circuit 25, after the light head count value is obtained based on the correct reproduction tiger poke data D _TRF is corrected in the remaining tracks number of values to be the seek, on the basis of the traverse signal S _T To repeat the down count.

Therefore, for example, after the seek operation is started at time t0 (FIG. 2), even if an erroneous count occurs in the conventional traverse count circuit 25, the target value signal changes to 0 [V] as indicated by a broken line. respect, since the correct reproduction tiger poke data D _TRF at time t1 and t2 are obtained count on the basis of which is corrected, to obtain a target value signal S ₂ which signal level is corrected to the correct target value it can.

During accordance connexion seek, By thus have to correct the target value signal S _2, the drive signal S _D for driving the optical head 4 is corrected to the correct signal level, as a result the target value signal S ₂ is 0 At the time of falling to [V], light head 4
Can be stopped at a recording track that is much closer to the target track than before.

Therefore, since the spectral head 4 does not need to be moved repeatedly, the time required for the entire seek to the target track can be shortened as compared with the related art.

In the seek amount correction circuit 31 contrary, have been made to correct the count value of the traverse counter circuit 25 based on the reproduction tiger poke data D _TRF obtained at different time points.

That is, in the seek amount correction circuit 30, the difference data D _REF1 between the target track data D _TJ and the reproduction track data D _TRF depends on whether or not the error is equal to or less than a predetermined value compared to the count value of the traverse count circuit 25. The traverse count circuit 25 is configured to correct the count value of the traverse count circuit 25. For example, when an extremely large defect or the like occurs on the magneto-optical disc 3, the traverse count circuit 25
Miscount occurs a large value equal to or greater than a predetermined value above the count value of 25, regardless of the value of the reproduction tiger poke data D _TRF is a correct value, there is a possibility to remain the count value is not corrected.

Therefore, in the seek amount correction circuit 31, the reproduction track data D intermittently obtained when the optical head 4 is moved.
_TRF1 and D _TRF2 obtain the count value of the traverse signal S _T during the reproduction tiger poke data D _TRF1 and D _TRF2 is obtained with obtaining difference data D _REF2 mutual error between the value and the count value of the difference data D _REF2 is predetermined when the value below based on the reproduction tiger poke data D _TRF, by correcting the count value of the traverse counter circuit 25 continues even when a large erroneous count occurs the count value in the seek amount correction circuit 30 is not corrected reproduced track The count value can be corrected at the timing when the data _DTRF is obtained.

That is, in the seek amount correction circuit 31, the reproduction track data is supplied to the subtraction circuit 40 having a latch circuit (not shown).
D _TRF is applied to obtain difference data D _REF2 between two successively obtained reproduction track data D _TRF1 and D _TRF2 , and this is applied to the comparison circuit 41.

Counting circuit 42 on the other hand, the control signal S _C2 which rises at timing latched reproduction tiger poke data D _TRF from the subtracting circuit 40 receives with the traverse signal S _T, with up-counts a count value based on the traverse signal S _T after outputting the count value based on the control signal S _C2, it is adapted to reset.

During the resulting reproduction tiger poke data D _TRF1 and difference period data D _REF2 is obtained the D _TRF2, to obtain a count data D _REF3 representing the number of optical head 4 is transected ivy recording tracks on the basis of the traverse signal S _T it can.

The comparison circuit 41 detects an error between the difference data D _REF2 and the count data D _REF3 , and outputs a control signal _{SC 3} to the count value correction control circuit 43 when the error is equal to or _smaller than a predetermined value.

The count value correction control circuit 43 latches the difference data D _REF1 output from the subtraction circuit 32 based on the control signal S _C3 , and then outputs it to the traverse count circuit 25 via the input circuit 24, and the traverse count circuit 25 _Is corrected to the value of the difference data D _REF1 .

Thus, when the erroneous count value of the traverse count circuit 25 is small, the count of the traverse count circuit 25 is performed via the seek amount correction circuit 30 and when the erroneous count value is large, it is possible to correct the target signal S ₂ by correcting the values. As a result, the drive signal _SD is corrected, and the optical head can be moved to a position closer to the target track than before, and the time required for the entire seek to the target track can be shortened accordingly.

In the above configuration, the reproduction tiger poke data D _TRF and target tiger poke the value of the difference data D _D1 with the data D _TJ starts the seek is excisional the traverse count circuit 25, the traverse count circuit in the traverse signal S _T which is obtained when the
The count value of 25 is counted down and output. As a result, the target value signal S ₂ to the optical head 4 approaches the target track signal level decreases is obtained, the optical head 4
Is driven and controlled on the basis of the target value signal S _2.

Reproduced track data obtained during seek
D _TRF and difference data D _REF1 between the target track data D _TJ and
Based on the comparison result between the remaining tiger poke data D _N obtained from the traverse count circuit 25 reproduced tiger poke data D _TRF
Is determined whether or not the reproduction track data D is correct.
If the value of _TRF is correct, the count value of traverse count circuit 25 is corrected based on this, and the signal level of drive value signal _SD is corrected accordingly.

Further, two consecutive reproduction track data D _TRF1 and D _TRF1
The difference data D _REF3 and _TRF2, reproduction data D based on the count data D _REF3 of the traverse signal S _T which is obtained during
_It is determined whether or not the value of _TRF is correct. If the value of the reproduction track data D _TRF is correct, the count value of the traverse count circuit 25 is corrected based on the value, and the drive value signal _SD is The signal level is corrected.

Accordingly, in the optical head 4, the corrected drive signal S _D
As a result, the vehicle can be stopped at a position much closer to the target track than in the prior art.

According to the above configuration, by correcting the erroneous count of the traverse count circuit using the reproduced track data obtained at the time of seeking, the optical head can be stopped at a position much closer to the target track than in the related art.

Therefore, since it is not necessary to repeatedly move the spectral head, the time required for the entire seek to the target track can be shortened.

In the above embodiment, the case where the count value of the traverse count circuit is corrected using two seek amount correction circuits has been described. However, the present invention is not limited to this. Only one of the correction circuits may be used.

Further, in the above-described embodiment, the case has been described where the traverse signal is simply down-counted by the traverse count circuit to form a target value signal that monotonically decreases. However, the shape of the target value signal is not limited to this. It can be widely applied, for example, when the signal level changes in shape.

Further, in the above-described embodiment, the case where the two seek amount correction circuits are individually configured has been described. However, the present invention is not limited thereto. For example, the seek amount correction circuit may be configured by an arithmetic processing circuit. In such a case, two circuits may be integrated into one circuit.

Further, in the above-described embodiment, the case where the present invention is applied to a magneto-optical disk device has been described. However, the present invention is not limited to this. For example, a compact disk device (CD), a read-only memory device (CD RO
M), it can be widely applied to optical disk devices such as information recording / reproducing devices using optical disks.

H Effect of the Invention As described above, according to the present invention, the time required for the entire seek to the target track can be reduced by correcting the drive signal of the actuator equipped with the optical head using the reproduction track data obtained during the seek. Can be further shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a magneto-optical disk device according to the present invention, FIG. 2 is a signal waveform diagram for explaining its operation, and FIG. 3 is a characteristic curve showing a moving speed of an optical head during a seek. FIG. 4 is a block diagram showing a conventional magneto-optical disk device, and FIGS. 5 and 6 are schematic plan views showing the recording format thereof. 1, 20 ... magneto-optical disc device, 3, 19 ... magneto-optical disc, 4 ... optical head, 5 ... address decoder circuit,
6, 22 ... seek amount setting circuit, 7, 23 ... target signal generation circuit, 13 ... seek control circuit, 15 ... actuator drive circuit, 16 ... actuator, 30, 31 ... seek amount correction circuit.

Claims (1)

(57) [Claims] 1. A traverse counting circuit for counting the number of recording tracks to a target track based on a traverse signal when an optical head moves during a seek, and traverses a recording track based on a count value of the traverse counting circuit. An optical head driving means for moving the optical head in the direction, and outputting reproduction track data of the recording track traversed by the optical head based on a reproduction signal obtained when the optical head traverses the recording track. An optical disk device, comprising: an address decoder circuit for performing correction; and a seek amount correction circuit for correcting the count value of the traverse count circuit based on the reproduced track data.